Image processing apparatuses such as Multi Function Peripherals (MFPs) or copying machine which are provided with color printing functions are coming into wide use. In such image processing apparatuses, the processings are carried out of forming an image based on the print data, forming an electrostatic latent image on a charged photoreceptor by impinging it with light according to the image, developing it by making charged toner get adhered to it, and transferring that toner image to a sheet via an intermediate image transfer member such as a transfer roller or a transfer belt.
In the above image processing apparatus, adjustment is necessary in order to transfer accurately on to the sheet the image instructed by the print data, and in particular, in image processing apparatuses that carry out product printing which are required to output accurate prints, it is necessary, for example, to carry out advanced adjustments such as adjusting the positions at the front and back surfaces to accuracies of several fractions of a millimeter, or to adjust the color difference to a level that cannot be detected visually, etc. Since such advanced adjustments cannot be made visually, special measuring instruments (color measuring instruments, density measuring instruments, digitizers, etc.) are used to carry out color compensation, density compensation, position correction, etc. (these are collectively called “calibration”).
Regarding the above color compensation, an image forming method has been disclosed, for example, in Japanese Unexamined Patent Application Publication No. 2005-27276, in which a prescribed test chart is formed on the image transfer member, the test chart is detected by a chromaticity detection section, the result of measuring the test chart by the measuring instrument is stored, and, based on the detected result and the stored result of measurement, the detection error of the chromaticity detection section is corrected.
The measurements for calibration do not directly measure the accuracy of the image processing apparatus, but a sheet (hereinafter referred to as a patch sheet) is output in which specific patterns (in the case of color compensation, patterns with density variations for each of the colors of Yellow, Magenta, Cyan, and Black, which patterns are referred to hereinafter as measurement patches) are printed out at prescribed positions, and the shifts are verified by measuring this patch sheet using measuring instruments such as a color measuring instrument, a density measuring instrument, a digitizer, etc., and these shifts are fed back to the image processing apparatus as parameters thereby ensuring that the target values are reached.
Therefore, various complicated operations become necessary in order to carry out calibration, such as, to begin with, the measuring person operating the image processing apparatus and outputting the patch sheet corresponding to the measuring instrument, setting that patch sheet in the measuring apparatus, carrying out measurement of the patch sheet by operating the measuring instruments, and after that, operating the image processing apparatus and inputting the measurement results of the patch sheet. Further, since these operations are made by the measuring person himself or herself, there were that problems that a patch sheet was output that did not correspond to the measuring instrument or the measurement results were input wrongly, etc.
The present invention was made in view of the above problems, and the main purpose of the present invention is to provide an image processing apparatus and a control program by which it is possible to carry out adjustments easily as well as definitely using a measuring instrument.